Collapsible chamber pump



Nov. 8, 1955 Filed Jan. 5 1951 L. A. MAILLOT COLLAPSIBLE CHAMBER PUMP 7Sheets-Sheet 1 Leo/7 14/f'h9d Mail/0) r In van for Nov. s, 1955 L. A.MAILLOT 2,722,893

COLLAPSIBLE CHAMBER PUMP Filed Jan. 5, 1951 '7 Sheets-Sheet 2 In var/farLeo/7 A/f'red Mail/o? 1955 A. MAILVLOT COLLAPSIBLE CHAMBER PUMP 7Sheets-Sheet 3 Filed Jan. 5, 1951 f h w h ed w MN A m 8 #0 H1 ey Nov. 8,1955 v L. A. MAlLLOT 2,722,893

COLLAPSIBLE CHAMBER PUMP Filed Jan. 5 1951 7 Sheets-Sheet 4 "f7\\\\\\\\\\\\\\i i a Q 4 E;

Nov. 8, 1955 L. A. MAILLOT COLLAPSIBLE CHAMBER PUMP 7 Sheets-Sheet 5Filed Jan. 5 1951 N 1955 L. A. MAILLOT 2,722,393

COLLAPSIBLE CHAMBER PUMP Filed Jan. 5, 1951 7 Sheets-Sheet 6 In van 7% rLeon X/f'red fl7m7/07 Nov. 8, 1955 1.. A. MAILLOT COLLAPSIBLE CHAMBERPUMP 7 Sheets-Sheet 7 Filed Jan. 5, 1951 Am? 6y United States PatentOfiice 2,722,893 Fatented Nov. 8, 1955 2,722,893 COLLAPSIBLE CHAMBERPUMP I Lon Alfred Maillot, Vanves, France Application January 5, 1951,Serial No. 204,648 Claims priority, application France January 17, 195610 Claims. (Cl. 103-148) It is known to use pumps whose principal memberconsists of a deformable elongated tubular enclosure and a device forlocally tightening the tube so as to produce an obturation displaceablealong the enclosure. The fiuid to be pumped is sucked up upstream fromthe obturation and discharged downstream therefrom. pumps, which haveconsiderable advantages of simplicity in construction, absence ofvalves, accurate operation (for they are exactly volumetric undercertain conditions) and complete separation of the fluid to be pumpedfrom lubricants, are frequently used mainly for medical purposes, suchfor example as blood transfusions, but they have not found extensive useindustrially. On one hand, the rubber tubes used as the elongatedtubular enclosure, deteriorate rapidly and hence are unsatisfactory tomeet conditions of an industrial plant on account of the amplitude andthe frequency of the required deformation. On the other hand, the meansemployed for producing the obturation of these tubes and displacing theregion of obturation along the tube exert on the tubes not onlytransverse stresses but also longitudinal stresses that fatigue the tuberapidly.

The present invention remedies the above inconveniences. It consistsessentially in employing, instead of a complete elastic tube, such as arubber tube, an elongated enclosure of very flat section, of which onewall only is deformable with a very small amplitude of deformation,whereby considerally longer life for the tube and accuracy of operationare obtained. Moreover, the

deformations of said wall are produced by adjacent ele-.

mentary pushers which exert their action perpendicularly to thelongitudinal axis of the elongated enclosure. These pushers, which donot form any seal, do not need to be made with the accuracy required,for example, in making pistons.

.In order to obtain a compact construction and simplify the control ofthese pushers, it is expedient to arrange the elongated tubularenclosure clrcularly in a plane disposed at right angles to the pumpdrive shaft, which carries rollers or rollsadapted to act upon thepushers Whose displacement, in principle substantially normal to the enclosure surface, is limited by an adjustable external abutment.

According to the present invention, it is preferable to substitute forthe displacement of the pushers, normally the enclosure surface atilting motion relative to a stationary abutment that maintains inplace, with very little play, one side of the pusher, while a secondabutment, which is an adjustably movable abutment, permits a limitedmovement of the other side of the pusher. Preferably, the adjustableabutment is an internal abutment the adjustment of which may becontrolled during the pump operation by means of a controlling deviceconcentric with the pump shaft.

In the present case, there are shown two forms of pump which have provenvery eflicient. One of these forms is a continuous flow pump with avarying feed and with a single discharge under high pressure. Such aSuch pump is suitable for all uses where an accurate discharge isdesired, to be varied at will during the pump operation, withoutrelative displacement of metallic parts in the liquid handled andwithout the use of valves, for example, in the case when differentreagents in chemical plants or injecting gasoline, water orantidetonating products' into internal explosion engines arecontinuously handled.

The other of these forms is concerned with a discontinuous flow pumphaving a single feed and having a number of independent discharge ports,namely for injecting directly into the cylinders of an engine an exactquantity of liquid fuel.

There has further been provided a pump in which the flat tube thatconstitutes the principal member, is constantly maintained obturated byspring-loaded pushers whose successive rising, results in disengaging orliberating only the tube region subjected to the action of a determinedpusher, the pump being herein called a reverse control pump.

In view of the fact that these pumps operate with a very smalldeformation of the membrane, there has been provided a membraneconsisting of one or more very thin metal foils, preferably combinedwith a membrane of plastic material, for example the plastic materialformed from polymerized fiuorinated hydrocarbons.

Finally, various improvements according to the invention have beenapplied to pumps for feeding internal combustion engines, moreparticularly those operating on the Beau-de-Rochas cycle.

Ail intricate problem occurring in the operation of these engines isthat of metering air-and-gasoline.

As a first approximation, it is necessary to send into the cylinders aweight of gasoline in proportion to the weight of air. The weight ofgasoline will be almost proportionate to its volume. The weight of airwill be proportionate to its volume, its absolute pressure and itstemperature.

The speed of rotation of the to the volume.

The absolute pressure and the temperature are those prevailing betweenthe throttle and the valves (pressure at the valves).

There are thus available three parameters to define the Weight of air;it is therefore necessary to utilize them in order to measure the weightof gasoline to be supplied.

In the fuel injecting pump according to the invention the device forregulating the height of elevation of the pushers is made dependent on amember whose displacements are automatically determined by a pressureparameter, namely by the pressure at the valves of the engine to be fed,and preferably also by a temperature parameter.

Several forms of pumps designed according to the invention Will now bedescribed, by Way of example, with reference to the accompanying, moreor less schematic, drawings in which:

Fig. 1 is a transverse section of the tubular enclosure engine isdirectly related according to the present invention;

Fig. 2 is a longitudinal axial section of a continuous pump according tothe present invention, showing on the left a pusher raised and on theright a pusher depressed;

Fig. 3 is a transverse section through the line III-III of Fig. 2;

- Fig. 4 is a schematic plan view taken substantially along the lineIVIV of Fig. 2;

Fig. 5 is an evolution along the mean line of the ushers of the pump;

Fig. 6 is a longitudinal axial section of a discontinuous pump forinjecting gasoline into the cylinders of an engine;

Fig. 7 is a schematic sectional plan view corresponding to Fig. 6;

Fig. 8 schematically shows an evolution along the mean line of thepushers of a pump that is the same as that of Fig. 6 except that thereare several rollers;

Fig. 9 is a longitudinal axial section of a reversed control pump forfuel injection;

Fig. is a transverse section through the line X-X of Fig. 9;

Fig. 11 shows an evolution of the kind shown in Figs. 5 and 8;

Figs. 12, 13, I4 schematically show various modified forms of membraneof the tubular enclosure; and

Fig. shows, in axial section, a pressure governor that may be interposedbetween an ordinary gasolinesupplying pump and the injection pumpaccording to invention.

Similar numerals refer to similar parts throughout the several views.

schematically (Figs. 1- and 5), the tubular enclosure 1 forming pumpchamber, is defined, on one hand, by a plane metallic surface 2 which ispolished or glazed and, on the. other hand, by a thin membrane ofdeformable material 3. This membrane may be made for example ofsynthetic rubber unaffected by gasoline (if the liquid to be handled isgasoline). I may use also a plastic material, for example the plasticmaterial formed from polymerized fiuorinated hydrocarbons. The membrane3 is clamped between the surface 2 and a frame having spaced lateraledge portions 11a and 11b (Fig. 2) parallel to the longitudinal axis ofthe frame and one or more transverse portions 11c (Fig 5). The termparallel is used in the sense of equidistant without being limited tostraight lines. In the embodiment illustrated in Figs. 2 to 5, thetubular enclosure is annular so that its longitudinal axis is arcuate.The. lateral edge portion 11a of the frame is formed by an annularshoulder of a casing 11 while theoppositelateral edge portion 11b isformed by' a flange on a stationary sleeve 2%. The lateral edge portions11a and 11b of the frame define the lateral edges of the enclosure 1while the ends of the enclosure are closed by the transverse portion orportions 111:. By providing a plurality of transverse portions He, theenclosure is divided into a number of separate chambers.

Along the length of the enclosure there are disposed a series ofadjacent pushers 4 guided in a manner to exert. only a force normal tothe longitudinal axis of enclosure 1. The pushers 4 are acted uponbyrollers 5 (Fig. 5) adapted to rotate on their axles and to have a motionof translation parallel to the longitudinal axis of enclosure 1, forexample in the direction of the arrow F. It will be seen that thesuccessive displacements of the pushers cause the successive obturationof the enclosure from the left to the right, with the result that, foreach chamber of the enclosure 1, there occurs suction upstream from theobturation through the passages 6, 7 and a discharge downstreamtherefrom through the passages 8 and 9.

In order that the obturation may be maintained constant, it is evidentlynecessary that a pusher 4 acts before the next upstream pusher stops itsaction, that is to say that the: roller 5 has a sufficient diameter. Itis further necessary, when the roller 5 reaches the right end of thechamber, that the next roller has commenced the obturation, that is tosay (Fig. 5) that the distance 21 between the inlet and outlet passagesof a chamber must be less than or equal to the distance 2 betweencenters of successive rollers.

The seal constituted by the obturation may correspond to a number ofdepressed pushers above the unit. In order to determine the length ofthis seal it is evidently necessary to take into account twoconsiderations: on one hand, to have an absolutely efiicient seal, whichwould necessitate a seal as long as possible and, on the other hand, toobtain a discharge as great as possible, which would lead to a seal asshort as possible.

The pump shown in Figs. 2 and 3 has a shaft 12 rotating the disc 13ball-mounted thereon. The disc 13 carries axle ends 15 located apartfrom one another and on which there may rotate ball bearings 16 whoseoutside races perform the role of rollers 5 which bear on the pushers 4acting upon the circular membrane 3 maintained by its two sides on thesurface 2 of the machine framework, and which may be detached from thesurface. The surface 2 and membrane together form the flat tubularenclosure constituting the essential member of the pump proper. Eachpusher is retained, on one hand, by a stationary outer abutment rim 17leaving a very small clearance to the pusher edge and, on the otherhand, by an inner abutment rim 18 whose axial position may be modified.Indeed, this abutment rim 18 is rigid with a shaft end 19 centered inthe stationary sleeve 20 and which carries threads cooperating with anut 21. This shaft end is, on the other hand, rigid with a lever 22 andit is clear that the displacement of the lever 22 in one or the othersense lowers or raises the abutment 18. it is further clear that thepusher, which oscillates practically about its setting on the stationaryabutment 17, may thus be given a tilting motion from zero (the memebrane 3 applied completely against the glaze surface 2) to a maximum,thereby varying the volume under the membrane 3 and the discharge of thepump.

The ball-mounting of the disc 13 permits the latter to apply evenlyagainst all the rollers 5.

In the case of a continuous pump (Figs. 4 and 5) there exist on eachhalf-circumference two sets of pushers 4A, 4B (or two working chambers),to cooperate with the three rollers 5 spaced 120 apart from one another.The discharge ends of each set are interconnected, through passages 8,and connected to the outlet 9, the passages 8 being made in the pumpbody. The feed ends are connected, through the passages 6 of somewhatlarger diameter, with the inlet 7.

The operation of the pump is readily understandable by referring inparticular to Fig. 5 which illustrates the sequence of operation. Therollers 5 are supposed to move in the direction of the arrow F. It willbe seen that there is always at least one roller which obturates' apusher of a working chamber. In the position shown, the right-handroller is about to leave the pushers of the set 48. The second rollerhas already obturated the passage so that no communication can takeplace between the discharge and the obturation. At this moment, thedischarge of the chamber corresponding to the pushers 43 stops during afraction of revolution, but the third roller (the left-hand one) causesfull discharge of the chamber corresponding to the set of pushers 4A.The cyclic oscillations of the instantaneous discharge are thus verysmall.

Thedischarge will be still more regular if the number of workingchambers and number of rollers are increased.

The speed of rotation of such a pump may be selected at will: nosynchronization being necessary, and in all cases for which the use ofthe pumps is foreseen a series of speeds may be combined at best withthe angle of lever 22 and the feed pressure, in order to obtain thedesired results.

Figs. 6: and 7 show a pump for direct injection, for example, into thecylinders of an internal combustion engine, for example a four cylinderdiesel engine. The number of working chambers here is therefore equal tothe number of cylinders. Each of those working chambers. has a set ofpistons, such as 4A, 4B, 4C, 4D. It is further supposed that thereexists only one roller 5 mounted onthe disc 13. in this case the ball isdiscarded and the mounting of the disc 13 is rigid. All the: admissionsare interconnected, as previously, through passages 6 while the inlet isdesignated by reference 7. There are as many discharge ports 9A, 9B, 9C,9]) as there are chambers, their discharge ports not beinginterconnected.

SUIfiCient in each set thereof. It is however preferable A reducednumber, at least two, of pushers are to employ three or four pushers(three in the case shown in Figs. 7, 8) in order to obtain a less abruptrise ofpressure and a more regular jet proceeding from the workingchamber.

The various discharge ports are connected each to the injector of acylinder.

It is very necessary that the speed of the pump (and hence the drivespeed of the roller) be synchronized with that of the engine to be fed.In' the case of a single roller this speed must be that of the camshaft.For two revolutions of the engine crank-shaft, that is to say for thetime of the cycle, the roller attacks successively, as can be seen inFig. 8, the sets of pushers 4A, 4B, 4C, 4D, the discharges of thecorresponding chambers being connected to the cylinders in the desiredorder.

The time of injection is determined by the pump. In the case of Fig. 7where the sides of the three pushers form with one another an angle ofabout 15, the time of injection may be evaluated in the following way:when the roller 7 attacks the first pusher, nothing occurs but anobturation of the feed and a confinement, under the two next pushers, ofthe liquid to be injected. When the roller attacks the second pusher(the position in Fig. 8) and then the third one, the injection occurs,that is to say during about 15 angle that separates two successive edgesof pushers or during 30 on the crank-shaft, which is a good time ofinjection for a diesel engine. This time may easily be varied bychanging the number, and hence the angle, of the pushers.

The shifting of the pump shaft with respect to the crank-shaftdetermines the beginning of the injection in the cycle. This shiftingmay be modified in the course of running, if the piping is flexibleenough,.by rotating slightly the pump body.

When the injection is not for an engine of the diesel type but for afour-stroke explosion engine, it would be inadvisable to shorten thetime of injection in order that the latter might occur only upon arotation of the crank-shaft through 30", since the injection maythus beoperated during a good portion of the suction stroke. On the other hand,as these engines have high speeds, it is not expedient to subject thepump to useless. stresses. It is therefore of advantage to employseveral rollers, as indicated schematically in Fig. 8. If there arethree in number (as in the case of Figs. 2 and 3), the speed to beimparted to the pump will be equal to the third of the speed of thecamshaft, that is, to the sixth of the speed of the crank-shaft. Thetime of injection,.multiplied by three, then becomes in the order of 90that will be placed at best into the angle of 180 representing thesuction time.

It will be seen that, while a roller presses down the pushers of aworking chamber, all the pushers of the other chambers are raised andconsequently both the feed and the discharge are in communication. Allthe non-working circuits are therefore under the feed pressure up to theinjectors. This does not present any inconvenience, for the usualinjectors 30 (Fig. 8) are maintained closed, or opened and protected bya check-valve.

In contrast, it is an important advantage, especially for the injectionof gasoline, that the chambers be well filled up, which permits themaintenance with greater facility of the volumetricity of the pump for.carrying out airand-gasoline metering. I

It is sometimes preferred that the non-working circuits should benormally obturated by the pump. This can be attained by means of thepump shown in Figs. 9 to 11, where the membrane is normally appliedagainst the support surface, this pump herein being called a reversedcontrol pump. As shown in these drawings, the parts corresponding tothose of Figs. 2 and 4 are designated by the same numerals with additionof a hundred. It will thus be seen that the membrane 103 is normallyapplied against the surface 102 by the pushers 104 subjected each to theaction of a strong spring 25. The

pushers are released successively by the roller mounted on the shaft115, the whole assembly being rotated by the shaft 112. The height oftherelease of the pusher-pistons may be regulated in the course of 'run-;ning by means of the thrust ball bearing 26, 'serew-" threaded part 27cooperating with the pump body and lever 28 permitting of rotatingthis*sc'rew-threaded part. his clear that the spring 25 raises thepusher '104 immediately after the roller 105 passes. l

The chambers fill up during only a very shortinterval prior to thedischarge. It is therefore tobe expected that this filling, for a givenfeed pressure and for a given shifting of the lever 28, should decreasewith the speed of the pump andthat, consequently, the characteristic ofthe discharge in function of revolutions is not a straight line but is aconvex curve that becomes inflected when the speed increases. This is,however, without importance since no metering is to be efifectedjit willbe sufficient to increase a little the elevation of the pushers, byacting upon the lever 28 for example with the aid of an ac celeratorattached to this lever. In this way there will even be obtained anadvantage in that the engine will not speed up untimely, the pump being,in effect, auto-' regulating.

In Figs. 12 to 14 there are shown some modified forms of membrane.

It will be seen in Fig. 12 that between the surface 31 and the pusher 32there is interposed, as described above, a plastic non-metallic membrane33, and that between this membrane 33 and the pusher there is interposeda metal disc 34 sufiiciently flexible to follow the deformations of themembrane 33,:and sufficiently strong to protect the membrane from theedges of pushers 32 during the operations.

In Fig. 13 the plastic membrane is removed and replaced by an all-metalmembrane 35 jammed between two plastiowashers 36"to form a thoroughlytight outward joint, in such a way as to allow the-membrane to moveupwards a few tenths of a millimeter required for its operation. Thisupward displacement necessitates, in fact, a slight pull on the outerand inner joints. These lateral joints, however, may be avoided byreplacing the membrane, constituted by a thin metallic foilof Figs. 12and 13, by an assembly of thin metallic foils 37 (Fig. 14). Referringnow to Figs. 6 and 15, it will be seen how, in

the case of an explosion engine operating on Beau-'de-' Rochas cycle, itis possible automatically to take in ac-' count the pressure of theintake manifold, and also the temperature, in a manner to ensure acorrect air-and gasoline ratio. I A membrane piston 42 is mounted on theshaft 19 and" a nut 44 is screwed onto a threaded extension 19a of theshaft and applied against one end of a set of Belleville washers 43acting as a spring the other end of which bears against the pump body.

The membrane 42 receives, on its lower side, the abso-.

lute intake manifold pressure through the port 45 and, on}; its upperside, atmospheric pressure through the port 46.

By changing the number of Belleville washers it is possible to modifythe flexibility of the spring. By tightening or loosening the nut 44 theinitial tension is changed.

If it is assumed that the intake manifold pressure prevailing in piping61 is equalto the atmospheric pressure (this is the case of full load ofthe engine), the membrane 42 subjected to the same pressure on bothsides does not come into action; the equilibrium establishes itselfbetween the load of pushers 4 (depending only upon the injectionpressure selected so as to' be constant) and the compression load ofspring 43. A height of elevation of the pushers is then well defined.

If the gas throttle is closed, the intake manifold pressure decreasesand the membrane 42,under the influence of the atmospheric pressurewhich becomes preponderant, transmits to the system in equilibrium adownward stress that breaks the previous equilibrium. The downwarddisplacement thus produced releases the spring 43, its contractiondecreases and. the system becomes stabilized to a new position ofequilibrium such that the height of elevation of the pushers is lesserthan previously. The discharge of gasoline has diminished. as a functionof the pressure. parameter.

The change in the number of washers of the spring 43 permits ofadjusting the variation in the discharge in exact function of thevariation of the pressure parameter, this being obtained by adjustmentin the workshop.

The tightening of the nut 44, which also modifies the equilibrium, maybe. elfected on the engine. in operation. This nut may be actuated byhand or by means of a thermostat adapted to introduce a correction oftem-- perature or else concurrently with av possible manual correction.This manual correction may be justified for example by a desire'toincrease the feed at starting.

For aircraft (or automobile in mountains) it is possible automaticallyto make the system responsive to altitude by substituting, at 46, avacuum for the atmospherie pressure, either by vacuum pump or by meansof a vacuum capsule.

Gasoline flows in through a port 7 and flows along an. annular passage50. The discharge passages 9A, 9B, 9C, 9D (see also Fig. 7) have theiroutlet ends disposed. on the external cylindric surface of the pump andoriented. so that the discharge pipes may rapidly take paralleldirections.

It. isof advantage to feed the pump according to the invention at aregular and controlled pressure since it is clear that the admissionpressure influences the filling of the cylinders and that the variationin admission pressure provides additional means for acting upon thedischarge. This is why a pressure governor (Fig. 15) is interposedbetween the usual feed pump (which is for example a membraneauto-regulating pump that supplies the fuel at a pressure in the orderof l kg./crn. and. the pump according to the invention.

This governor is of a well known type having a membrane 53. by which itis separated into two chambers. Into the upper chamber 62 gasoline flowsin through a fitting 63, passes through a ball-valve 64 and fiows outthrough a fitting 65 to pass into a fitting 7 of the pump according tothe invention. The membrane carries a needle-valve 66v which raises theball and permits gasoline tofiow into the chamber 62. A screw 52 isadapted to act, through the intermediary of a spring 67, upon the.membrane and, consequently, to define the pressure selected for theadmission of gasoline into the pump according to the invention. Thisdevice-has also the advantage of damping pulsations of the feed pump.

According to the invention, while the gasoline feed pressure prevails inthe upper chamber 62., the lower chamber 68 is connected, for examplethrough pipes such as 61, to all or a portion of thepressure at thedistributing valves, whereby it is possible to vary the supply ofgasoline as function of this pressure.

It. will be understood that the pump described for a four-cylinderengine may easily be modified and adapted for an engine having anynumber of cylinders.

The injectors hereinabove referred to are shown schematically in Fig. 8.The arrangements provided accord ing to the invention may haveapplications to all installations, it being immaterial whether theinjectors be placed in a combustion chamber itself or ahead of theadmission valve. It is preferable to employ closed rather than openinjectors, in order to render the injection pressure independent fromthe discharge, but this is not absolutely necessary.

-What is claimed is:

I L. A pump of the character described comprising a supportv having a,plane surface, a plane elastic element adapted to rest upon said surfacewhen no pressure is exerted between said elastic. element and saidsupport, a frame having a longitudinal axis, spaced lateral edgeportions parallel, to saidv longitudinal axis and portionssubstantiallytransverse with respect to said longitudinal axis, saidlateral edge portions and transverse portions.

I frame tiltably about an axis parallel to the lateral edges of saidenclosure and adapted to press said elastic element inwardly againstsaid surface, and actuating means movable parallel to the lateral edgesof the enclosure and successively acting on the pushers to cause the successive tilting of said pushers.

2. A pump according to claim 1 in which the actuating means are rollingmeans acting on the pushers.

3. A pump according to claim 2 comprising a plurality of said tubularenclosures the admission ducts of which are united together to form acommon admission and the discharge ducts of which are also unitedtogether to form a common discharge.

4. A pump according to claim 2 comprising a plurality of said tubularenclosures the admission ducts of which are united together and thedischarge ducts of which are separately connected to the points ofutilization.

5. A pump according to claim 1 in which the actuating means comprisestwo successive means acting on the pushers, the distance between saidsuccessive means being smaller than the distance between the ends of thetubular enclosure.

6. A pump according to claim 1 in which the actuating means comprisestwo successive means acting on the pushers, the distance between saidsuccessive actuating means being greater than the distance between theends of the tubular enclosure, said pump working against a predeterminedpressure which is at least equal to the admission pressure.

7. A pump according to claim 1 comprising a rotating shaft and in whichthe longitudinal axis of the said frame is curved according to an arcconcentric to the axis of said rotating shaft and in which the meansacting on the pushers is carried by said shaft.

8. A pump or the character described comprising a support having a planesurface, a plane elastic element adapted to rest on said surface when nopressure is exerted between said elastic element and .said support, aframe having a longitudinal axis, lateral edge portions parallel to saidlongitudinal axis and portions substantially transverse with respect tosaid longitudinal axis, said lateral edge portions and transverseportions tightly pressing said elastic element against said surface soas to define, between said surface and an intermediate portion of saidelement, a tubular enclosure having spaced lateral edges bounded by saidlateral edge portions of the frame and closed ends bounded by saidtransverse portions, admission and discharge ducts extending:

through-said support and opening into opposite end portions of saidenclosure, the admission of fluid under pressure through said admissionduct separating said intermediate portion of the elastic element fromsaid surface, a plurality of adjacent pushers mounted on said frametiltably about an axis on one side of said enclosure and parallel to thelateral edges of said enclosure, said pushers extending transverselyacross said enclosure and being tiltable about said tilt axis to presssaid elastic element. inwardly against said surface, means mountedvonsaid frame on the. opposite side of said enclosure. from said tiltaxis and adjustably limiting the tilt of said pushers, and actuatingmeans movable parallel to the longitudinal axis of the frame andsuccessively acting on the pushers to cause the successive tilting ofsaid pushers.

9. An intermittent discharge pump comprising a housing, a pump shaftrotatively mounted in said housing, a stationary support fixed to saidhousing and having a plane surface perpendicular to the axis of saidshaft, a membrane resting on said surface, a frame having radiallyspaced inner and outer arcuate portions concentric with said shaft andcircumferentially spaced radial portions, said arcuate and radialportions tightly pressing said membrane against said surface so as todefine between said surface and intermediate portions of said membranebounded by said frame a plurality of circumferentially extending tubularenclosures having closed ends, admission and discharge ducts extendingthrough said support and opening into opposite end portions of each ofsaid enclosures, the admission ducts of said enclosures being connectedto a common inlet passage, a plurality of sets of adjacent pushersmounted on said frame between said radial portions, said pushersextending radially across said enclosures and being tiltably supportedat one end by said frame, said pushers being tiltable to press saidmembrane against said surface, a common non-rotating circular abutmentmounted in the housing concentrically with said shaft, said abutmentbeing movable axially and being engageable with said pushers to limitvariably the tilting movement of said pushers and actuating meanscarried by said shaft for successively tilting said pushers as saidshaft is rotated.

10. A pump according to claim 9 further comprising an enclosure providedin said housing, a diaphragm dividing said enclosure into two chambers,fluid connections respectively from said chambers to two points ofdifferent pressure, connections between said diaphragm and said abutmentlimiting the tilting of the pushers and means biasing said abutment anddiaphragm toward a selected position, whereby said abutment is movableagainst said bias by difierences of pressure in said chambers, therebycontrolling the amount of tilting of said pushers.

References Cited in the file of this patent UNITED STATES PATENTS 34,190Baldwin Jan 21, 1862 1,874,667 Wada Aug. 30, 1932 1,922,196 Butler Aug.15, 1933 2,341,257 Wunsch Feb. 8, 1944 2,412,397 Harper Dec. 10, 19462,435,902 Reggio Feb. 10, 1948 2,447,265 Beardsley, Jr. Aug. 17, 1948FOREIGN PATENTS 455 Great Britain 1853 113,026 Australia Sept. 11, 1940546,884 Germany July 1, 1930 909,631 France Jan. 4, 1946

